1. Field of the Invention
This invention pertains to improved sweetening agent delivery systems comprising a high intensity sweetening agent protected by a coating of polyvinyl acetate and having prolonged sweetness release. The sweetening agent delivery system is prepared by adding a solution of a high intensity sweetening agent to a melted mixture of polyvinyl acetate and a plasticizing agent and evaporating the solvent. A waxy material and an emulsifying agent are blended into the mixture which is then cooled and granulated to a desired particle size. The sweetening agent delivery systems may be used in a wide variety of ingestible products such as chewing gum compositions, hard and soft confections, and beverages.
2. Description of the Prior Art
High intensity sweetening agents are natural or synthetic compounds which have a sweetening intensity greater than sugar (sucrose) and a caloric value lower than sugar at equivalent sweetness levels. High intensity sweetening agents are well known in the art and are widely substituted for sugar in many low calorie and noncariogenic ingestible compositions.
Examples of high intensity sweetening agents are water-soluble natural sweetening agents such as dihydrochalcones, monellin, Stevia Rebaudiana (steviosides), and glycyrrhizin; water-soluble artificial sweetening agents such as 1,2-benzisothiazol-3(2H)-one 1,1-dioxide (saccharin and its salts, a commercially available product from PMC Specialty Group Inc., Cincinnati, Ohio), cyclohexylsulfamic acid (cyclamate and its salts), and the potassium salt of 6-methyl-1,2,3-oxathiazin-4(3H)-one-2,2-dioxide (Acesulfame-K, a commercially available product from Hoechst Celanese Corporation, Somerville, N.J.); proteins such as thaumatin (Talin, a commercially available product of Tate & Lyle Products, Reading, United Kingdom); chlorodeoxysugar derivatives (such as Sucralose, a commercially available product of McNeil Specialty Products Company, Skillman, N.J.); and dipeptides such as N-L-alpha-aspartyl-L-phenylalanine 1-methyl ester (Aspartame, a commercially available product of the Nutrasweet Company, Deerfield, Ill.) and L-alpha-aspartyl-D-alanine N-(2,2,4,4-tetramethyl-3-thietanyl)amide (Alitame, a commercially available product of Pfizer, New York, N.Y.). Each of these sweetening agents has a distinct sweetening intensity greater than that of sucrose and this sweetening intensity is well documented. For example, the following sweetening agents have the sweetness intensities set out below.
______________________________________ Sweetness Intensities of Various High Intensity Sweetening Agents SWEETNESS COMPOUND INTENSITY* ______________________________________ 1, 2-Benzisothiazol-3(2H)-one 1, 1-dioxide 300.times. (Saccharin and its salts) Cyclohexylsulfamic acid 30.times. (Cyclamate and its salts) N-L-alpha-Aspartyl-L-phenylalanine 180.times.-200.times. 1-methyl ester (Aspartame) Potassium salt of 6-methyl- 1,2,3-oxathiazin-4(3H)-one- 160.times. 2,2-dioxide (Acesulfame-K) 200.times. 4,1',6'-Trichloro-4,1',6'-trideoxy- 600.times. galactosucrose (Sucralose) L-alpha-Aspartyl-N-(2,2,4,4- 2000X tetramethyl-3-thietanyl)-D- alaninamide hydrate (Alitame) Dihydrochalcones 1500.times. Monellin 1500.times.-3000.times. Steviosides 250.times.-300.times. Glycyrrhizin 50.times.-100.times. ______________________________________ *Compared to sucrose.
Because each high intensity sweetening agent is chemically and physically distinct, each sweetening agent is a challenge to use in an ingestible composition. For example, many high intensity sweetening agents lose their sweetness intensity quickly when used in ingestible products such as chewing gums and confections. Saccharin, stevioside, Acesulfame-K, glycyrrhizin, and thaumatin have an associated bitter taste or off-note. Certain intense sweeteners are unstable or sensitive to moisture, temperature, and pH value. For example, Aspartame is unstable in the presence of aldehydes, ketones, and moisture. Solid Sucralose turns dark during prolonged storage or at elevated temperatures.
To prolong sweetness release and stabilize sensitive sweetening agents, many sweetening agents are encapsulated within a coating layer. Although encapsulation can prolong sweetness release and stabilize sensitive sweetening agents to an extent, these methods are not always satisfactory. For example, Aspartame is particularly difficult to encapsulate using conventional mixing and spray coating techniques because Aspartame crystals are rod-like, needle-like, and dendritic in shape and are particularly difficult to wet. Attempts to coat Aspartame crystals with mixtures of fat and lecithin using conventional mixing and spray techniques result in poor wetting and spotty coating of the core material.
U.S. Pat. No. 4,435,440, issued to Hough et al. and assigned to Tate and Lyle plc, discloses sweetening agents which comprise chlorodeoxysugar derivatives.
U.S. Pat. No. 4,343,934, issued to Jenner et al. and assigned to Tate & Lyle plc, discloses crystalline sucralose for use in food stuffs, beverages, and confections.
U.S. Pat. No. 4,927,646, issued to Jenner et al. and assigned to Tate & Lyle plc, discloses a codried or spray dried composition consisting of about 20% to about 80% Sucralose and a water-soluble oligosaccharide, by dry weight.
PCT patent application Ser. No. WO 89/08672A, priority date May 15, 1987, to Wm. Wrigley Jr. Company, discloses a chewing gum composition having controlled sweetness wherein the gum contains an effective amount of Sucralose.
U.S. Pat. No. 4,375,430, issued to Sklavounos and assigned to Pfizer Inc., discloses the preparation and purification of certain dipeptide sweetening agents including Alitame.
U.S. Pat. No. 4,774,094, issued to Carroll et al. and assigned to Nabisco Brands, Inc., discloses the use of stabilized L-aspartic acid derivatives in comestibles containing greater than about 2% moisture by being formulated with cooked, aqueous hydrogenated starch hydrolysates having a moisture content of about 10%.
U.S. Pat. No. 4,384,004, issued to Cea et al., discloses solid particles of Aspartame encapsulated by a coating material selected from the group consisting of cellulose, cellulose derivatives, arabinogalactin, gum arabic, polyolefins, waxes, vinyl polymers, gelatin, and zein.
U.S. Pat. Nos. 4,122,195 and 4,139,939, issued to Bahoshy et al., discloses a spray dried mixture of Aspartame, a film forming agent, and a material such as gum arabic or the reaction product of a compound containing a polyvalent metallic ion, with an ungelatinized acid-ester of a substituted dicarboxylic acid.
U.S. Pat. No. 4,374,858, issued to Glass et al., discloses a sweetened chewing gum comprising Aspartame having improved sweetness stability when Aspartame is coated on the surface of the chewing gum.
U.S. Pat. No. 4,375,430, issued to Sklavounos and assigned to Pfizer, Inc., discloses the preparation and purification of certain dipeptide sweetening agents including Alitame.
U.S. Pat. No. 3,389,000, issued to Toyonaka et al disclose drying process for preparing granular coated nucleoside-5-phosphates. The coating layers may be edible animal and plant fats melting between 40.degree. C. and 100.degree. C. such as hydrogenated oils including soybean oil, cottonseed oil, almond oil, castor oil, linseed oil, mustard oil, olive oil, grapefruit seed oil, palm oil, palm kernel oil, rapeseed oil, and rice bran oil.
U.S. Pat. No. 4,293,572, issued to Silva et al., discloses a dispersion of an emulsified fat with a solution of dextrin, Saccharin, or a polysaccharide, which is applied to a food product as a barrier against moisture.
European patent application No. 81110320.0, published Jun. 16, 1982, to Ajinomoto-Co., Inc., discloses a stabilized dipeptide-based sweetening composition comprising in percentages by weight (a) from 20% to 60% of solid fat, (b) from 10% to 30% of emulsifier, (c) from 10% to 30% of polysaccharide, and (d) not more than 30% of a dipeptide sweetening agent. The compositions are prepared by spray coating the sweetening agent, or by heating and mixing a mixture of sweetening agent and coating material, cooling the mixture, and then pulverizing the mixture to obtain powder or granules.
U.S. Pat. Nos. 4,752,485 and 4,597,970, both issued to Sharma et al., disclose a sweetening agent delivery system, and a chewing gum incorporating the delivery system, respectively, wherein the delivery system comprises a high intensity sweetening agent coated with a mixture of fatty acid or wax, lecithin, and a glyceride. The delivery system protects and controls release of the sweetening agent. U.S. Pat. No. 4,804,548, issued to Sharma et al., discloses a sweetening agent and flavoring agent delivery system wherein the delivery system comprises a core material comprising a mixture selected from the group consisting of sweetening agents and flavoring agents, wherein the core is coated with a mixture of fatty acid or wax, lecithin, and a glyceride.
U.S. Pat. No. 4,722,845, issued to Cherukuri et al., discloses a cinnamon flavored chewing gum which contains a sweetening agent delivery system which comprises an amino acid or dipeptide sweetening agent encapsulated with a hydrogenated fat, a polyethylene wax having a melting point of 106.degree. C. or greater, and a glyceride.
U.S. Pat. No. 4,816,265, issued to Cherukuri et al., discloses a chewing gum composition containing a sweetening agent delivery system which consists essentially of (a) at least one solid natural or artificial high intensity sweetening agent present in an amount from about 0.01% to about 50%, (b) an emulsifying agent present in an amount from about 0.5% to about 20%, and (c) polyvinyl acetate present in an amount from about 40% to about 93% and having a molecular weight range from about 2,000 to about 14,000.
U.S. Pat. No. 4,711,784, issued to Yang, discloses a chewing gum composition containing an encapsulation composition which comprises a blend of polyvinyl acetate having a molecular weight range from about 20,000 to about 100,000 and a hydrophobic plasticizer.
Hence, a number of encapsulation methods are known for coating high intensity sweetening agents which have varying degrees of effectiveness in protecting and controlling the release of the core material. None of these methods, however, are entirely satisfactory for encapsulating difficult to coat high intensity sweetening agents and extending sweetness release Accordingly, an encapsulation method which can uniformly coat a sweetening agent with a flexible polymeric coating layer and intimately bind the sweetening agent to the polymeric matrix to delay sweetness release is desirable. The present invention provides such improved sweetening agent delivery systems having prolonged sweetness release. The sweetening agent delivery systems may be used in a wide variety of ingestible products such as chewing gum compositions, hard and soft confections, and beverages.